Half of all money spent on advertising is wasted. But we just don't know which half. In recent years, marketing professionals have been trying to use neuroscience to locate the "buy button" in our brain, which if pressed would make us buy their stuff. It's the holy grail: a way of knowing, in advance, which ads are going to work and are worth spending money on, and which ones would flop. The promise, from both marketers and some neuroscientists, is that our brains can, effectively, be hacked. But does it work? Presenter/producer: Jolyon Jenkins

"Memory athletes" compete to see who can remember the most random numbers in an hour. Or else to memorise decks of playing cards. Memory training is big in China, where there are TV game shows for memory contests, and where parents pay good money to get their children trained in memorisation techniques. Everyone thought the Chinese were invincible, and that we were at the limits of what could be memorised - until 2019 when a group of North Korean teenagers arrived at the world championships, smashed a bunch of records, and returned to Pyonyang. Since then, nothing has been heard of them. What's their secret? And why does North Korea want to dominate the world in this obscure sport? Presenter/Producer: Jolyon Jenkins

Ever since the middle ages, pieces of the True Cross, and other relics such as saints' bones, have been sold to the gullible. But now the trade in bogus relics has moved online, to the fury of traditional Catholics. They are even more alarmed at the sale of "genuine" relics, which is also picking up pace as monasteries and convents close and their treasures come on the market. In theory selling a relic is an offence under Church law, warranting immediate excommunication. But what is a genuine relic, and how its provenance proved? Jolyon Jenkins goes on a deep dive into a world where faith, science and archaeology collide. Producer/Presenter: Jolyon Jenkins, BBC Audio in Bristol

There are millions of planets out there that could contain intelligent life. We can't look at them all, so which should we focus on? Using nothing but statistics, astronomer Fergus Simpson predicts the aliens will be living on small, dim planets, they'll have small populations, big bodies, and will be technologically backward. This goes against many astronomers' working assumption that the earth is typical of inhabited planets - and that our sun is an ordinary star in an ordinary galaxy. Fergus argues that this is an example of the "fallacy of mediocrity" which we fall for time and time again, whether it's in our assumptions about gym membership, taxi drivers, or train overcrowding. Presenter/Producer: Jolyon Jenkins

As telescopes get better, astronomers are seeing more and more things in the night sky. Sometimes they can't explain them. Is it unreasonable to suggest that they might have found evidence of alien civilisation, or at least some form of extra-terrestrial life? Call it right and they could get the Nobel prize. Get it wrong and it could be career suicide. Only those at the very end of their career, with a well-established reputation, can afford to take the chance. Jolyon Jenkins reports on some of the cases where scientists have stuck their necks out, and how badly it can go wrong for them if their findings are less robust than they thought. Producer: Jolyon Jenkins

Jolyon Jenkins investigates reports that people with severe dementia, or who haven't spoken for years, can sit up and have lucid conversations just before they die. Victorians called the phenomenom "lightning before death" and recently it's been described as "terminal lucidity". It seems incredible, but some in the medical community are taking it seriously. Producer: Jolyon Jenkins

Many animals can navigate by sensing the earth's magnetic field. Not humans, though. But might we have evolved the sense but forgotten how to access it? 40 years ago a British zoologist thought he had demonstrated a homing ability in humans. But his results failed to replicate in America and the research was largely discredited. But new evidence suggests that our brains can in fact detect changes in the magnetic field and may even be able to use it to navigate. Jolyon Jenkins investigates, and talks to a Pacific traditional seafarer who has learned to navigate vast distances across the ocean with no instruments, and who describes how, when all else fails, he has been able to access what he calls "the magic". Is the magic still there for all of us, just waiting to be rediscovered? Producer: Jolyon Jenkins

Jolyon Jenkins explores Esperanto, the language designed to bring world peace and harmony. Invented in the late 19th century, Esperanto is simple to learn, with a logical grammar, a vocabulary drawn from European languages, and no irregularities. Its creator, Ludovic Zamenhof, hoped that it would become a second language that everyone could speak, eliminating international misunderstandings. For a while, Esperanto flourished, and there was even a tiny Esperanto-speaking state in what is now Belgium, but both Stalin and Hitler saw it as subversive and tried to crush it. Jolyon tries to learn the language and to discover what remains of those early ideals. He finds elderly Esperantists playing word games in a Cardiff pub, Brazilian spiritists who believe that Esperanto is the language in which the dead converse, and a small Esperanto-speaking enclave in Goma, in the war-torn eastern Democratic Republic of Congo (some of whom learned it under the misapprehension that Esperanto was an organisation that handed out money). Is Esperanto a blindingly obvious and sensible idea, or a ludicrously utopian one? Presenter/producer: Jolyon Jenkins.

Who do you want to read your old emails when you die? Are the dead entitled to privacy?

Jolyon Jenkins attends an international whistling competition in Los Angeles to meet the people who want whistling to be taken seriously as a musical art form. The competition is organised by the "Whistling Diva", Carole Ann Kaufman, herself a former international whistling champion. "If it comes from the heart, it's art," she says. But even though there have been featured whistling instrumentalists, in the big band era for instance, whistling struggles to be thought of as more than a novelty act. Even the whistlers at the convention find it hard to persuade their own families that their talent is worth celebrating. It's even led to the break up of marriages. Occasionally, though, a whistler does make it to the (comparative) big time. Geert Chatrou is a Belgian whistler who won an international competition in 2004. he is now semi-professional and has recorded and performed with symphony orchestras and jazz bands. So - will a new champion emerge this year? Presenter/producer: Jolyon Jenkins.

For centuries, people have dreamed of perpetual motion machines, and many ingenious inventors have tried to come up with devices that will keep going forever with no external input. All have failed. But in recent decades there's been a new take on the idea. A large community of people now believe that it is possible to build a machine that will create free energy. Not only will it keep going forever, but it will also be able to do useful work. They say that this does not contravene any laws of physics because the machines harvest quantum "zero point energy" from the environment. Indeed, many believe that such machines have already been successfully invented, but that they have been suppressed by the forces of Big Oil, who do not want to see their profits hit. There are many conspiracy theories, and talk of "men in black" who put the frighteners on inventors and even - in extreme cases - apparently go as far as to kill them. Undeterred, reporter Jolyon Jenkins buys plans for a free energy machine online. For less than £100 it's going to give him energy independence from the big power companies. But it turns out to be tricky to build. Will he get it to work, or will the men in black get to him first? Presenter/Producer: Jolyon Jenkins.

Jolyon Jenkins meets the people who believe in trepanning - drilling a hole in the head. They do it for what they think are good medical reasons. Many ancient civilisations practiced trepanning, for reasons we can only guess at, but in modern times the practice dates from the 1960s and attempts by people in the counterculture to expand their consciousnesses. These enthusiasts thought they could get more blood into the brain if the skull was a bit more elastic, and therefore get "high". Unfortunately they didn't always do it very well. and sometimes had to make several attempts before they penetrated the skull. More recently, their focus has shifted away from blood, and towards cerebrospinal fluid. They argue that one role of CSF is to flush away the brain toxins that are implicated in dementia. Trepanning, they think, can improve the flow of CSF. Bits of their argument are potentially plausible, and they have at least one proper scientist on their side. And trepanning is, in itself, not an especially dangerous operation - most brain surgery starts with drilling a hole in the skull. But the medical profession won't take them seriously, and so they are forced to go to Ecuador to find a surgeon who will do it ... or do it themselves in their garage. Are they dicing with death? Or are they up against a hidebound medical profession not prepared to look at the evidence? Presenter/Producer: Jolyon Jenkins.

Across Britain, thousands of people have stopped paying council tax, water rates and speeding fines. They think they have the law on their side, thanks to the 1215 Magna Carta treaty between King John and the Barons. They argue that the present Queen has breached her obligations under the treaty and so has in effect deposed herself and even become a traitor. As a result, all laws passed by parliament are invalid, the courts are shams, and government officials are imposters. Instead, they swear an oath of allegiance to a group of members of the House of Lords. The rebels meet in a Facebook group with 13,000 members. In truth, few people join the group because of an interest in constitutional history - most arrive there because they are in a desperate financial or legal situation, feel that the system is stacked against them, and are looking for a way out. The group offers a system to deal with the authorities that - if used effectively - will supposedly get them off your back. For nearly a year, Jolyon Jenkins followed the group's members, even signing an oath himself. But does the system work? Over the months, members of the group become increasingly frustrated at the authorities' refusal to take their arguments seriously. The frustration eventually leads to a secret plan to seize a crown building, as they believe Magna Carta entitles them to. Presenter/Producer: Jolyon Jenkins.

Jolyon Jenkins meets the people who want to swim a mile through freezing cold water. This isn't like a quick dip on New Year's Day - it takes about 40 minutes to swim a mile. As the swimmers battle the second law of thermodynamics, only the fit, or fat, will make it. Some swimmers acclimatise by sitting in icy paddling pools in their gardens and sleeping without bedclothes. Others pile on the calories to build bulk. But apart from the danger of hypothermia, the risks are legion: cold shock as you enter the water, loss of brain function or motor control leading to drowning, and non-freezing cold injury that can leave sufferers with permanent pain in their extremities. Acclimatisation can even increase the risks, by lowering the temperature at which you start to shiver and generate heat. No wonder that not everyone thinks ice swimming is a good idea. So why do the ice swimmers want to do it? Jolyon travels to the ice swimming world championships in Bavaria to find out. Presenter/producer: Jolyon Jenkins.

Jolyon Jenkins investigates the network of private Christian schools in Britain that teach that evolution untrue, homosexuality is wrong, and that wives should submit to their husbands. These schools use the Accelerated Christian Education (ACE) curriculum, originally devised by a fundamentalist Texan who thought that all education needed to assume the literal truth of the bible. The entire curriculum, including science, makes continual reference to God's plan. It promotes creationism, and the false idea that humans and dinosaurs co-existed on earth. The system requires children to sit in "offices" - desks screened off from their neighbours - and work their way in silence through the "packets of accelerated Christian education" and then take multiple choice tests. The system requires no teachers, only "supervisors". Pupils do not usually take A levels but special Christian exams. Although some pupils make it to university and have successful careers, Jolyon speaks to others who feel that the system has not served them well. Are ACE pupils being well prepared for life in modern Britain? For years, Ofsted has appeared to show little interest in the contents of the ACE curriculum but a few recent inspections of ACE schools suggest that this may be changing. Presenter/Producer: Jolyon Jenkins.

For 50 years, one of the most powerful psychoactive drugs, LSD, has been illegal in Britain. The authorities do not want you to alter your state of consciousness. In 2016, the government passed a law banning all psychoactive substances except caffeine, alcohol, and nicotine. But can you enter altered states of consciousness without drugs? Since the 60s, experimental "psychonauts", deprived of psychedelics, have been trying. Sensory deprivation, flotation tanks, hyperventilation, and light machines are just some of the methods that are claimed to be able to put you in trance states, expand your consciousness, or even produce spiritual experiences. Jolyon Jenkins, who has never taken LSD or even had a spiritual experience, investigates, even going so far as to construct his own retro "altered states of consciousness induction device". Will his consciousness expand, or retain its current dimensions? Producer/presenter: Jolyon Jenkins.

In a new documentary series uncovering stories from the left field, Jolyon Jenkins reports on the extreme treatments bald men are putting themselves through. They are commissioning laboratories in China to manufacture unproven, untested, and potentially dangerous drugs to cure their hair loss. Is it a hiding to nothing or will they succeed where the drug companies haven't? Men have always gone bald but now they're not putting up with it. An explosion of online forums has created a "hair loss community". "It's a silent epidemic", says Spencer Kobren, founder of The Bald Truth forum. "Hair loss doesn't physically hurt, but we liken it to a cancer of the spirit". Kobren runs a weekly radio show in which callers express their pain and frustration. Joe isn't sure whether it would be worse to have actual cancer: "I'd rather have one or two good years of hair," he says. "I want to hear the birds sing, I want to walk on the beach, I want to be free of this terrible disease." In an attempt to deal with encroaching baldness, some young men are reading up on the latest medical research into hair loss and seeking out chemists to manufacture molecules they hope will work. There's no guarantee that the chemicals they are buying are pure, and the buyers have no real idea of the correct dose; but it speaks to their desperation. Some of them report unpleasant side effects. Few of them can show convincing hair regrowth. Presenter Jolyon Jenkins, a "hair loss sufferer" for two decades, investigates this subculture. Along the way he has a consultation for a hair transplant (£10-£15,000) and looks into "hair systems" - or as some call them, wigs. Does loss of hair really decrease a man's attractiveness significantly? And how did a normal part of being a man become a debilitating disease?

Annie, 35, wants a baby, but she doesn't have a partner. If she could afford it, she could go down the official and regulated route to a fertility clinic and get pregnant using donor sperm. But that could cost thousands of pounds. So instead, she's gone online and entered the world of unregulated sperm donation. Jolyon Jenkins investigates this shadowy world. It's illegal to sell sperm, but some men are making a living doing so. Others offer free sperm in return for "natural insemination", i.e. sex. Some women report that men who start by appearing to offer free sperm, gradually exert pressure on them to have sex. But what of those who want neither money nor sex in return for their sperm? Jolyon discovers the world of the "super donor" - men who compete to inseminate as many women as possible, in an acknowledged bid to spread their genes as widely as they can. Their activity can border on the obsessive."It is a bit like stamp collecting really," says one. "I devote three hours per day to it, through travelling to donate or arranging my spreadsheets or doing my photo albums of the children". The risks to women and their children are obvious - sexually transmitted infection, hereditary conditions unwittingly passed on, and accidental incest between half-siblings. If women could afford to use the official channels, they would be much safer. Instead, they are being driven into the hands of sexual adventurers, serial liars, and hobby eugenicists. Presenter/producer: Jolyon Jenkins.

Jolyon Jenkins meets the people zapping their brains with DIY electrical devices, lasers and electromagnets. They want to learn faster, dream better, and even have spiritual experiences. Some of it might even work. There's evidence that putting a weak electric current through your skull can help you learn, and induce a "flow" state. The US military is experimenting with devices that seem to help snipers improve their marksmanship. One woman who tried it says that what she found was that "electricity might be the most powerful drug I've ever used in my life." Such talk is just what the garage experimenters want to hear. Real drugs are hard to get licensed, but many of the experimenters hope that a strap-on electrical head gadget will be able to give the same kind of effects, but without having to go through the regulatory hoops. There's money to be made, they hope, from early adopters who see their brains as just another device that can be improved through a bit of hacking. Producer/presenter: Jolyon Jenkins.

Build a better mousetrap, so the saying goes, and the world will beat a path to your door. But is it true? There are over 4,500 mousetrap patents but this doesn't stop inventors coming up with new designs - even though the basic spring-loaded trap was designed in the nineteenth century and, you might think, is unimprovable. Jolyon Jenkins talks to people who dream of riches from mousetraps, and one who has even managed it. And he invents his own, ultra-humane, hi-tech trap. Will it impress the professionals? Presenter/Producer: Jolyon Jenkins.

Jolyon Jenkins reports on the world of electronic voice phenomena (EVP) - the community of people who believe that the dead can speak to us through radio transmissions and white noise. The technique was introduced to the English speaking world by a mysterious Latvian, Dr Konstantin Raudive, who travelled to Britain in 1969 with recordings of Hitler, Churchill and Stalin speaking from beyond the grave. The method is now a mainstay of paranormal investigators. Jolyon unearths tapes from 40 years ago made at a key séance held by Dr Raudive in Gerrards Cross. Raudive eventually came to believe that a budgerigar called Putzi was passing on messages from a dead 14 year old girl. Jolyon speaks to EVP current practitioners, and to a man who believes that his recordings of animal noises also contain messages. The claims are improbable, but they tell us interesting things about human perception: about our ability to construct meaning from meaningless sound, and about how our brains naturally fill in the gaps where information is incomplete. Optical illusions are well known, but we are equally prone to being fooled by audio illusions. Sound artist Joe Banks suggests that, while EVP researchers may be carrying out parapsychology experiments, they are unwittingly doing conventional psychology experiments.

Jolyon Jenkins reports on the men fighting a liberation war against what they see as female tyranny, and the separatist "men going their own way" - who've given up on women. Such men take their principles from the film "The Matrix", in which only those who take the "red pill" see the true nature of reality, while those who take the "blue pill" live in ignorance of the true state of affairs - which, in this case, is that society is organised for the benefit of women, and that men are seen as disposable and worthless. We live, they think, in a "gynocracy", thanks to the remorseless march of feminism. But the movement is split. Some of them think that there is still time to organise and fight back. They think that the system can be changed, and that relationships between men and women recalibrated. But others are more radical. They believe that male/female relationships are inherently toxic, the system is unbeatable, and that the only sane strategy for a man is to exit from the gynocracy while he still can, even if this means "living as a ghost" within broader society. Producer/presenter: Jolyon Jenkins.

Jolyon Jenkins reports on one man's attempt to create a new nation - a libertarian utopia - in what he says is unclaimed land between Serbia and Croatia. He has money and supporters, and half a million people have signed up for citizenship. But it's not been easy for Vít Jedlicka, Czech politician and president of "Liberland". Since he planted his flag on these marshy 7 square kilometres on the banks of the Danube in 2015, his supporters have been arrested, fined and jailed. He himself has been barred from entering Croatia. Neither Croatia nor Serbia seem to want to claim the territory, but that doesn't mean they want a zero tax libertarian enclave with no gun laws sitting between them. Jedlicka is not deterred though. He keeps up a busy schedule of international conferences, has appointed a full cabinet, and is busy opening embassies and bestowing proto-ambassadorships around the world. Jolyon Jenkins joins him as he and his foreign minister try to get back into Croatia and visit the territory he would eventually like to call home. Producer: Jolyon Jenkins.